Re: [PSUBS-MAILIST] Stainless Welding.

[<james@guernseysubmarine.com>]

Hi Dan.

Thanks for that.  I just wanted to verify welding the dissimilar metals is ok.

I'm MIG welding the stainless and i am using a special wire that is designed for dissimilar metals.  Im at work at the moment so i cant look up what it is, but i talked to the guy at Lincoln about it in some detail.  It cost a fortune as well!    :(

I suppose your probably right about the VBT corrosion issue.  I just dont like the idea of it rusting away under there without being able to do anything about it. But like you say, i can just replace it.  i can probably get some paint into it, and loads of silicone grease when its it use.

Also ive had a right game getting "proper" 316L for my through hulls.  Its amazing how many shops say "yeah, we've got that in" but as soon as you ask to see the certificates they change their tune to "ah, well its PROBABLY 316L".    If you didnt force the issue, they'd sell you any old rubbish lying about the workshop i'm sure.  Anyway, i've got a length of certified stuff sent over from UK now.

Better get on with some work...
James,

No problems with the two different metals but you should use a welding rod
that is designed for this application.  I have some at my shop but forget
the designation.  If you contact a welding supplier the will advise you of
what they have.  Use stainless rod for the stainless, steel rod for the
steel ,but this particular rod is for joining the two different metals.

Use as much stainless as you can afford on your sub.  For things that rub,
like hinge points, it will save you major corrosion and rust streaks in your
paint.  But, for something like a VBT, don't spend the money.  The tank just
sits there.  All the corrosion is on the inside.  Sure you can't see it to
inspect it, but if it's thick enough, it's not a big problem.  If it leaks
it will start with pinholes anyway.   If you make it with heavy wall
material it will last a long time.  You can cut it off and replace it with a
new one in ten years if you feel it needs changing.  Put the stainless in
places where you get the most for your money.

There's a reason the worlds navies don't build stainless steel ships.  The
price!  Maintenance and replacement part are sometimes cheaper.

Dan H.


----- Original Message -----
From: <james@guernseysubmarine.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, June 17, 2008 4:03 AM
Subject: [PSUBS-MAILIST] Stainless Welding.


Hi All.

As my sub will be used in the sea, ive decided to make some parts out of
stainless rather than mild steel.  In particular, i have made the hatch
hinge arrangement all again.  (I made it from mild steel to start with).
Here is a picture of the original brackets i made.
http://www.guernseysubmarine.com/index_files/Page10471.htm

Ive made the whole thing now again from 316L (no picture yet) and its all
assembled ready to weld to the conning tower.  Then i just thought of one
thing...

I will be welding 316L on the brackets straight onto A516 on the tower.  Can
anyone see any problems with that?  The welding of dissimilar metals
straight onto the hull?

I think it should be no problems as the throughhulls are the same principle,
but what do you all think?  Any problems that i havent thought about?

Thanks
James






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